If yes,is to prevent you from ventilating on the clothe used to cover the canvas head,the right thing to use is the masking tape but if you don't have,you can use nylon.
Just ventilate according to the direction of the net or place the cap on your head and mark the ear shape on the net using a marker or chalk and then ventilate
Pass the pin through a single hole on the swiss lace(the pin has a tiny hook at the tip)then hook about two strands of hair,pull it out from the hole and knot it.